The Ground Before is a prequel to the TV series, the 100.
91 years after a nuclear war destroyed the human race, or so they thought.
Grounders are descendants of people who were prepared for the war and are the only survivors who have adapted to take in the radiation. Lexa has trained her whole life to become a warrior, and to protect her people, and as her 16th birthday approaches, she is finally ready to take on the responsibility. Tension is breaking out between the 12 Clans of Grounders, but Lexa's only thought is to save her best friend, Costia. Lexa and Costia will do anything they have to to save the Woods Clan, and to restore peace between the 12 Clans.